In U.S. Pat. No. 4,219,559 there are described a number of N-heterocyclyl-4-piperidinamines having antihistaminic properties.
In European Patent Publication Nos. 0,999,139; 0,145,037 and 0,144,101 there are also described a number of N-heterocyclyl-4-piperidinamines as compounds having antihistaminic and serotoninantagonistic properties.
The compounds of the present invention differ from the prior art compounds essentially by the nature of the 4-piperidinyl substituent which is invariably a purinylmethyl or -hetero group.